This study is designed to integrate our pesticide exposure research across the Center cohort community within the Yakima Valley region of Washington. This will link our previous research on exposure pathways which has been conducted on a smaller scale with single spray events: pesticide spray drift studies describing chemical fate and transport, and exposure assessment studies, with emphasis on residential exposure factors, para-occupational exposures, human activity patterns, personal exposure and dose estimation. Children who live in agricultural communities are a vulnerable community having many potential yet not fully characterized exposures pathways related to their proximity to pesticide spraying in addition to the traditional pathways of take-home exposure, diet, drinking water, and residential pesticide use. The overall objective of our research is to understand how exposures at a community scale, involving multiple applications, crops, weather patterns, and human activities may contribute to non-occupational exposures of children following pesticide applications. Pesticide drift and dispersion will be evaluated using measurements and physical transport models we have benchmarked in our previous studies to field samples from actual spray events. Residential characteristics and land use will be assessed with crop data and pesticide application information from the current decision tools used for selecting chemical treatments. Participant's activity patterns will be assessed using a GPS tracking device that can be integrated into a spatial-temporal data set describing personal activity during spray episodes. Using these physical and behavioral exposure factors, this study seeks to identify the determinants of children's exposure to pesticides from the proximity pathway as estimated through urinary metabolites or other biomarkers. This study will bring innovative methods of exposure assessment to bear on the problem of pesticide spray drift, and in doing so will identify the best opportunities for applicator, community, or parental interventions.